2 Minute Medicine Rewind May 22, 2017


Aerobic or Resistance Exercise, or Both, in Dieting Obese Older Adults

Obesity is known to exacerbate age-related decline in physical function. In older adults, associated reductions in muscle and bone mass place patients at risk of frailty. Exercise has been shown to improve physical functioning in older adults and reduce muscle and bone loss. However, studies comparing aerobic exercise, known to improve cardiovascular health, to resistance exercise, improving strength, have not been previously performed. In this randomized controlled trial, 160 obese (BMI ≥ 30) adults aged 65 years or older were assigned to a weight management program plus one of three exercise regimens – aerobic training, resistance exercise, or both – or assigned to a control group with no program, with the primary outcome being a change in the Physical Performance Test score from baseline in 6 months. Secondary outcomes included frailty measures, body composition, bone mineral density, and physical function. The patients randomized to aerobic and resistance exercise demonstrated the greatest improvement in Physical Performance Test score with a 21% increase from baseline, compared to patients carrying out either aerobic (p=0.01) or resistance-based exercise (p=0.02) alone, who achieved an improvement of 14%. The combined group also had significantly greater increases in peak oxygen consumption, and strength (p<0.001). Body weight decreased by 9% in all exercise groups, but did not significantly change in control group. Lean muscle mass decreased less in the combination and resistance groups (3% and 5%, respectively) as did bone mineral density (1% and 0.5% respectively) (p<0.05). Overall, this study indicates that a combination of aerobic and resistance exercise may be the most effective method for improving functional status of older adults with obesity.

Association of Short Antenatal Corticosteroid Administration-to-Birth Intervals With Survival and Morbidity Among Very Preterm Infants

The use of antenatal corticosteroids (ANS) in preterm infants has been shown to reduce morbidity and mortality when administered 24 hours to 7 days before delivery. However, less is known about other, possibly narrower, administration-to-birth intervals. In this population-based cohort study, investigators analyzed data from the EPICE cohort study conducted from 2011 to 2012, which included 4594 singleton infants of gestational age 24-31 weeks. The authors studied the time from first injection of ANS to delivery, which was divided into 4 categories: no ANS, first injection <24 hours, between 24 hours and 7 days, or greater than 7 days. Outcomes included in-hospital mortality, composite of mortality and severe morbidity, and severe neonatal brain injury. Researchers found that any administration of ANS compared to no ANS was associated with a decline in mortality, with 50% risk reduction achieved with ANS use at 18 to 36 hours prior to delivery. Risk reductions for in-hospital mortality or severe neonatal morbidity were also observed when ANS was administered <24 hours (RR 0.7, 95% CI 0.6 to 0.9) and between 24 hours and 7 days (RR 0.7, 95% CI 0.6 to 0.8), but not greater than 7 days before delivery (RR 0.8, 95% CI 0.7 to 1.0). When examining in-hospital mortality and severe neonatal brain injury as separate outcomes, however, neonates still appeared to confer benefits from ANS administered more than 7 days before delivery. A simulated modeling analysis showed that ANS administration 3 hours prior to delivery decreased mortality by 26% compared to no ANS administration. This study therefore shows that ANS may be most beneficial in reducing neonatal morbidity and mortality if given only hours before delivery.

Effect of Combined Patient Decision Aid and Patient Navigation vs Usual Care for Colorectal Cancer Screening in a Vulnerable Patient Population

Screening programs for colorectal cancer (CRC) have helped reduce disease-related mortality. However, vulnerable populations, notably racial minorities, have seen lower rates of screening and thus are at higher risk of CRC-associated morbidity and mortality. In this randomized controlled trial, 265 participants aged 50 to 75 with no prior CRC screening, were randomized to receive a CRC screening decision aid before their clinician encounter along with support for screening completion by a patient navigator, or to a control group where participants viewed a food safety video before the encounter with usual care. The primary outcome was CRC screening completion within 6 months of the study. Researchers found that 62% of research participants were Latino, 23% black or mixed race, and 15% white. Most patients had a median income less than 20,000 USD (78%), 62% were uninsured or on Medicaid, and 38% had low literacy. In assessing the impact of the intervention, the authors noted that completion of CRC screening at 6 months occurred in 68% of the intervention group and 27% of the control group, representing a 40% increase (95% CI 29% to 51%, p=0.02). Women constituted 65% of the study population and had a 50% increase in screening compared to men with 21% (p=0.02). This study therefore demonstrates the value of a patient decision aid and patient navigator in improving CRC screening completion, particularly in vulnerable primary care patients.

Effect of Oral Iron Repletion on Exercise Capacity in Patients With Heart Failure With Reduced Ejection Fraction and Iron Deficiency

Iron deficiency is seen in approximately 50% of patients with heart failure with reduced left ventricular ejection fraction (HFrEF) and has been shown to independently predict reduced functional capacity and mortality. However, the efficacy of oral iron supplementation, which is both easily available and inexpensive, in heart failure is not well studied. In this randomized control trial, 225 adults with HFrEF (ejection fraction <40%) and iron deficiency (serum ferritin 15-100 ng/mL or serum ferritin 101-299 ng/mL with transferrin saturation <20%) were provided either oral iron polysaccharide 150 mg twice daily for 16 weeks or placebo to study the improvement in peak exercise capacity, measured as peak oxygen uptake (V̇o2) from baseline to 16 weeks. Secondary outcomes include 6-minute walk distance, plasma N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels, and health status as assessed by Kansas City Cardiomyopathy Questionnaire (KCCQ, range 0-100, higher scores reflect better quality of life). Researchers found that changes in peak V̇o2 at 16 weeks did not significantly different between oral iron and placebo groups (difference 21 mL/min, 95% CI -34 to 76 mL/min, p=0.46). There were also no significant differences between treatment groups in 6-minute walk distance, NT-proBNP levels, or KCCQ score. This study therefore shows that in patients with HFrEF and iron deficiency, high-dose oral iron supplementation does not improve exercise capacity over 16 weeks.

Safety and immunogenicity of a live attenuated influenza H5 candidate vaccine strain A/17/turkey/Turkey/05/133 H5N2 and its priming effects for potential pre-pandemic use

H5N1, a highly pathogenic avian influenza virus, has raised concerns of over potential pandemic. With vaccination remaining the most effective way of preventing influenza, a novel candidate vaccine strain has been developed. In this randomized double-blind, placebo-controlled trial, 152 adults aged 18 to 49 years were randomized to receive either two intranasal doses (0.25 mL per nostril) of live attenuated influenza vaccine (LAIV) H5N2 or placebo in a 2:1 ratio to assess immune response as measured by hemagglutination-inhibition, microneutralization assays, circulating follicular T-helper cells, and plasmablast cells in serum and whole blood. The second part of this study included a single intramuscular dose of the H5N1 booster vaccine. Researchers found that at 1 year of follow-up from initial vaccination and subsequent booster shot, 98% of participants had an increase in hemagglutination-inhibition titer greater than four-fold as early as day 7 compared to only 15% in the placebo group. The peak geometric mean titer for hemagglutination-inhibition antibodies in the previously LAIV H5N2 vaccinated group was also significantly greater in the intervention group when compared to placebo (p<0.0001). Critically, The LAIV H5H2 group showed higher cross-reactive hemagglutination-inhibition antibody titers against H5N1 (clades 1,, and 2.3.4) compared to the naive group (p<0.0001). The vaccine was well tolerated, with no serious adverse events. This study therefore shows that the LAIV vaccination against H5N2 induces a long-lasting memory immune response.

Image: PD

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